1. Field of the Invention
The invention relates to a display system and an image beam adjustment method thereof. Particularly, the invention relates to a three-dimensional (3D) display system using a pair of viewing glasses, and an image beam adjustment method thereof.
2. Description of Related Art
Ongoing development of display technology has led not only to displays that are light, thin and small, but also to displays that can generate three-dimensional (3D) images. 3D image display devices send different images to the left and right eyes of a user, which the user's brain interprets as a 3D image.
At present, there are two main types of 3D display device, i.e. a display that requires glasses and a display that does not require glasses. 3D glasses in turn include several types, the earliest being red and blue glasses, and more recent types including shutter glasses, and polarization glasses. Each of these types of glasses causes different images to be transmitted to the left eye and the right eye of the user, which are interpreted by the user as a 3D image. 3D shutter glasses are generally used in combination with various display devices such as a 3D liquid crystal television and a 3D projector, etc. to create a 3D effect.
Conventional shutter glasses include a front polarizer, a liquid crystal layer and a back polarizer. The polarization axis of the front polarizer is parallel to a polarization direction of an image beam emitted by the 3D display device, and the polarization axes of the front polarizer and the back polarizer are orthogonal to one another. The liquid crystal layer is disposed between the front polarizer and the back polarizer, and changes the polarization direction of the image beam in response to an applied operating voltage. Therefore, after the image beam passes through the liquid crystal layer, the polarization direction of the image beam can be parallel or perpendicular to the back polarizer, so that the image beam can pass through the back polarizer or can be blocked by the back polarizer. By cyclically applying the operating voltage to a left lens and a right lens of the shutter glasses, the shutter glasses can block the left eye and the right eye images sent by the 3D display device in different times, so that the left eye of the viewer can view a left eye image, and the right eye of the viewer can view a right eye image, which the user interprets as a 3D image.
However, the polarization directions of image beams of different 3D display devices on the market do not have a uniform specification, and thus different display devices may send image beams of different polarization directions, so that shutter glasses having a given polarization axis direction can be used in only in conjunction with display devices having the corresponding image beam polarization direction, which may increase production cost and the price of the glasses. Meanwhile, users have to buy different glasses to match different 3D display devices, which drives up the cost to use the technology and may discourage its widespread adoption.